Method for combating certain foliar diseases of plants

ABSTRACT

FUNGUS AND BACTERIAL FOLAIR DISEASES OF PLANTS ARE COMBATED BY APPLYING TO THE PLANTS AN EFFECTIVE BUT SUBSTANTIALLY NON-PHYTOTOXIC AMOUNT OF A COMPOUND HAVING THE STRUCTURAL FORMULA   1-((2-X,4-Y,5-Z-PHENYL)-NH-CO-O-),2,6-DI(C(-CH3)3-),   4-(C(-C*N)2=CH-)-BENZENE   IN WHICH X IS SELECTED FROM THE GROUP CONSISTING OF HYDROGEN AND CHLORO AND NITRO SUBSTITUENTS, Y IS SELECTED FROM THE GROUP CONSISTING OF HYDROGEN AND CHLORO AND FLUORO SUBSTITUENTS, AND Z IS SELECTED FROM THE GROUP CONSISTING OF HYDROGEN AND CHLORO SUBSTITUENTS, AT LEAST ONE OF X, Y AND Z BEING HYDROGEN.

United States Patent Office 3,825,662 METHOD FOR COMBATING CERTAINFOLIAR DISEASES OF PLANTS Roger Paul Cahoy, Overland Park, Kans.,assignor to Gulf Research 8: Development Company, Pittsburgh,

Pa. No Drawing. Filed Oct. 18, 1971, Ser. No. 190,395

Int. Cl. A01n 9/20 US. Cl. 424--300 2 Claims ABSTllACT OF THE DISCLOSUREFungus andhacterial foliar diseases of plants are combated by applyingto the plants an effective but substantially non-phytotoxic amount of acompound having the structural formula 1 1 H /CN YQ-N- -0 6:0

CN 2 ennu in which X is selected from the group consisting of hydrogenand chloro and nitro substituents,

Y is selected from the group consisting of hydrogen an chloro and fluorosubstituents, and

Z is selected from the group consisting of hydrogen and chlorosubstituents, at least one of X, Y and Z being hydrogen.

DESCRIPTION OF THE INVENTION animals, including humans. It has now beendiscovered that carbamyl fderivatives of this compound havingconsiderably higher molecular weights, which would therefore appear todilute the toxic structure on a weight basis, possess both theadvantages of high fungicidal and bactericidal activity and reducedtoxicity both to plants and warm blooded animals. The method ofpreparation of representative compounds is illustrated in the procedureswhich appear below:

Preparation of 3,5-di-tert.butyl-4-(2,4-dichlorophenylcarbamyloxy)benzylidenemalononitrile A reaction flask was charged with 8.5 g. (0.03mol) of 3,5di-tert.butyl;4-hydroxybenzylidenemalononitrile, 7.0 g.(0.037 mol) of 2,4-dichlorophenyl isocyanate, ml. of heptane and onedrop of triethylamine. The reactants were mixed by hand stirring andheated on a water bath at 50-55 C. Within several minutes, an exothermicreaction took place and the reaction temperature reached 70 C. Thereaction mixture was cooled, additional heptane was added and stirringwas continued. The material was collected on a vacuum filter and airdried. It melted at 85- 90 C.

Analysis-Calcd. for C H Cl N O C, 63.83; H, 5.36; N, 8.93. Found: C,63.33; H, 5.58; N, 8.77.

Preparation of 2,6-di-tert.butyl-4-(2,2-dicyanoviny1) phenylN-chloroacetylcarbamate Chloroacetyl isocyanate was prepared fromchloroacetamide and oxalyl chloride as described in Organic Synthe-3,825,662 Patented July 23, 1974 sis, vol. 46, p. 16 (1966). A reactionflask was charged with 8.6 g. (0.031 mol) of3,5-di-tert.butyl-4-hydroxybenzylidenemalononitrile, a catalyticquantity of 1,4-diazobicycle-[2.2.2] octane, 50 ml. benzene and 4.2 g.(0.035 mol) of chloroacetyl isocyanate. The reaction solution wasstirred for six days at ambient temperature under a nitrogen atmosphere.After cooling, a white crystalline material precipitated which wascollected on a vacuum filter. The compound was recrystallized frombenzene-heptane. It melted at 160-4 C.

Analysis.-Calcd. for C H C1N O C, 62.76; H, 6.02; N, 10.46. Found: C,61.94; H, 5.95; N, 10.62.

Preparation of 3,5-di-tert.butyl-4-(4-chloro-2-nitrophenylcarbamyloxy)benzylidenemalononitrile A reaction flask was charged with 5.6 g. (0.02mol) of 3,5 di-tert.butyl 4 hydroxybenzylidenemalononitrile, 2 drops oftriethylamine, 50 ml. of benzene and 6.0 g. (0.03 mol) of commerciallyavailable 4-chloro-2-nitrophenyl isocyanate. The reaction solution wasstirred for 12 hours at ambient temperature. The solvent was removed onthe rotary evaporator and the residue was stirred with hexane. Thecompound was collected on a vacuum filter and air dried. It melted at143-46 C.

Analysis.-Calcd. for C H CIN O C, 62.43; H, 5.24; N, 11.65. Found: C,62.46; H, 5.50; N, 11.79.

The melting points of other compounds appearing in the fungicidal testdata of this application are indicated:

bamyloxy)benzylidenemalononitrlle.

Foliar Fungicide Test Procedure for Powdery Mildew Spore Control onCucumbers (PMC) Test chemicals (20 percent active samples) formulated in0.05 percent MC-1500 methyl cellulose were applied to cucumbercotylendons using a pneumatic atomizing nozzle. After the spray was dry,the plants were placed in an inoculation chamber and dusted with powderymildew spores. The plants were maintained at a relative humidity of -100percent for 48 hours and then moved into the greenhouse. Results weredetermined after 10 days.

Foliar Fungicide Test Procedure For Leaf Rust Spore Control on Wheat(LRW) Cheyenne wheat plants, Triticum vulgare, approximately seven toeight days old and four to five inches tall are mounted on a compoundturntable and sprayed at 40 pounds pressure for 60 seconds withrespective candidate compounds at concentrations indicated. Candidatecompounds are prepared for spraying by dissolving in a suitable solventsystem and diluting to desired concentration with deionized watercontaining wetting and dispersing agents.

After drying, treated plants are dusted with spores of Pucciniarubigovera directly from diseased plants and then immediately placed inan incubation chamber maintained at 70 F. and plus RH. After the properincubation period, plants are removed to the greenhouse for diseasedevelopment.

lation to permit assessment, of control. Disease severity s Diseaseseverity (infection pressure) is determined by Foliar Fungicide TestProcedure for Apple Scab Spore Control on Apples (ASB) v McIntosh appleseedlings in vigorous growing condition, eight to ten inches tall, aremounted on a compound turntable and sprayed at pounds pressure with thecandidate compound at concentration indicated. Samples are prepared forspraying by dissolving in a suitable solvent (acetone, methyl alcohol,ethyl alcohol or other) and diluting to desired concentrations withdeionized water containing wetting and dispersing agents.

After drying, treated plants are spray-inoculated with a sporesuspension of Venturia inaequalis and immedi ately placed in anincubation chamber maintained at 70 F. and 95% plus RH. After hours inthe incubation chamber plants are removed to the greenhouse for furtherdisease development. Fourteen days after inoculation plants are observedfor disease development and control by counting the number of infectionloci on the three most heavily infected leaves per plant. Efectivenessof treatments is determined by direct comparison with inoculatedcontrols. Cyprex is used as a reference standard. All units of testinclude a minimum of three replicates.

Foliar Fungicide Test Procedure for Rice Blast Spore Control on Rice(RBD) Rice plants in fully developed second-leaf growth stage aremounted on a compound turntable and sprayed at 40 pounds pressure forseconds with the candidate compound at concentrations indicated.Approximately 150 ml. of test solution are delivered. Candidate samplesare prepared for spraying by dissolving in a suitable solvent (acetone,methyl alcohol, ethyl alcohol or other) and diluting to desiredconcentration with deionized water containing wetting and dispersingagents.

After drying, treated plants are spray-inoculated at 30 pounds pressurewith an aqueous spore suspension of Piricularia oryzae and thenimmediately placed in an incubation chamber maintained at F. and plusRH. After proper incubation time plants are removed to the greenhousefor disease development. Infection lesions are sufficiently developedwithin five days after inocudetermined by actual count of the'number"of'inf'ecti'on" lesions developing on untreated inoculatedcontrols. Effectiveness of treatment is determined by direct comparisonof the number of infection lesions appearing on the respective treatedplants compared directly withthose lesions appearing on untreatedinoculated controls. Phenylmercuric acetate is used as a referencestandard.

units of test include a minimum of three replicateswi Foliar ApplicationProcedure For Bacterial Leafy Spot Spore on Tomatoes (BLT) Bonny Besttomato plants approximately six to seven weeks old, in six to seven-leafgrowth stage, are mounted on a compound turntable and sprayed at'35pounds pressure for .50 seconds with the candidate compound atconcentrations indicated. Approximately 150 ml. of test solution isdelivered. Candidate samples are prepared for spraying by dissolving ina suitable solvent (acetone,

chamber maintained at 70 F. and 95 plus R-H. After 40 hours in theincubation chamber, plants are removed to the greenhouse for furtherdevelopment of infection lesions. Disease severity is determined bycount-of lesions present on six to seven treated leaves. Effectivenessof treatment is determined by direct comparison with inoculatedcontrols. Streptomycin sulfate is used as a reference standard.

Disease control (PMC, LRW, ASB, RBD, BLT) and phytotoxicity weredetermined using the following scale:

Disease Control (percent) 0=no control 3 :76-99 4=complete controlPhytotoxicity A=no effect B=some effect C=mediurn effect D=severe effectE=dead plants Disease control Concn. Chemical (P.p.m.) PMC LRW ASB RED 1BLT (CHa)aC 25o 4-D 4-. an -E l /CN HO- CH=C CN a)aC (CH) C 01 a a l 0CN ll C1 -NHCO CH=C CN (CHa)aC I (CHahC 3-A 3-A 3-A 0A O 0 CN ll llC1CHzCNHCO- CH=C 1 CN (CH3)3C C1 (CHahO 300 4-C 3-A 3-1) 1 l H ON 01(CHa)aC TABLE-Continued Disease control Concn Chemical (P.p.m.) PMC LRWASB RBD BLT a)aC o1 300 3-A 3-A o-A r P l 0N ahC (Clinic 300 3-A 3-A 2-A(I? /CN Ol-Q-NHCO- cn=o l CN ahC (011910 300 3'1. O-A 3A 0-A .1 @4310 0-CH=C\ i ON (CHa)aC (CHa)aC 100 0-D 0-A 4-A 04. 0-A N02 I 0 ON ll olNHo0- OH=O\ CN (CHa)aC (011910 3011 0-A 3-A 3-11 0-11 if f F-NHC 0- on=oCN 01 HM The preferred compound to use in a composition for I claim:

combating plant diseases is 3,5 di tert.butyl 4- (2,4dichlorophenylcarbamyloxy)benzylidenemalononitrile. Customarily suchcompositions are formulated with finely divided inert solid diluents andsurface active agents to yield wettable powders for use in aqueoussprays. A wettable powder containing the preferred compound may beprepared according to known techniques, using common diluents such asclays and diatomaceous earth, along with readily available wetting anddispersing agents. Suitable compositions for combating plant diseasesmay also be prepared in the form of dusts and Water dispersible pastes,using suitable solid diluents, solvents and thickening agents. Thepreferred compound, though higher in molecular weight than3,5-di-tert.butyl 4 hydroxybenzylidenemalononitrile, is more effectiveagainst some pathogenic organisms and at the same time is less toxic tosensitive plant species such as melons and cucumbers. The preferredcompound is particularly useful in combating diseases of fruit treessuch as, for example, apple scab and fire blight of pears.

References Cited 50 UNITED STATES PATENTS 3,694,483 9/1972 Cahoy er al260465 D 3,538,226 11/1970 Ozaki et a1. 424.404 3,592,912 7/1971ilshiyama et al. 424-304 55 ALBERT T. MEYERS, Primary Examiner L.SCH-ENKMAN, Assistant Examiner

